Cook egg noodles according to package directions; drain and set aside.

In a large skillet, heat olive oil over medium heat. Add onion and mushrooms; sauté until soft.

Add ground beef and cook until browned. Drain excess fat.

Stir in cream of mushroom soup, sour cream, salt, and pepper. Cook 2 more minutes.

Mix in cooked egg noodles and half of the cheese.

Transfer mixture to a greased 9×13-inch baking dish.

Sprinkle remaining cheese on top.

Bake at 350°F for 20–25 minutes until hot and bubbly.